release: v0.2.5 — 质量加固 + Bug修复 + 性能优化 + SQL扩展

src/sql/parser.ts

@@ -16,6 +16,8 @@ import type {
   DeleteStatement,
   CreateTableStatement,
   DropTableStatement,
+  AlterTableStatement,
+  TruncateTableStatement,
   ASTColumnDef,
 } from '../query/ast';
 import type { WhereCondition, OrderBy, SortDirection } from '../constants';
@@ -52,6 +54,10 @@ export class Parser {
         return this.parseCreateTable();
       case TokenType.DROP:
         return this.parseDropTable();
+      case TokenType.ALTER:
+        return this.parseAlterTable();
+      case TokenType.TRUNCATE:
+        return this.parseTruncateTable();
       default:
         throw this.error(`Unexpected token "${this.curToken.value}"`);
     }
@@ -426,6 +432,52 @@ export class Parser {
     return 'RESTRICT';
   }
 
+  // ===================================================================
+  //  ALTER TABLE
+  // ===================================================================
+
+  private parseAlterTable(): AlterTableStatement {
+    this.expect(TokenType.ALTER);
+    this.expect(TokenType.TABLE);
+    const tableName = this.expectIdentifier('table name');
+
+    // ADD COLUMN / DROP COLUMN
+    let action: 'ADD' | 'DROP';
+    if (this.curTokenIs(TokenType.ADD)) {
+      action = 'ADD';
+      this.nextToken();
+      // Optional COLUMN keyword
+      if (this.curToken.type === TokenType.IDENTIFIER && this.curToken.value.toUpperCase() === 'COLUMN') {
+        this.nextToken();
+      }
+      const col = this.parseColumnDef();
+      return { type: 'ALTER_TABLE', name: tableName, action, column: col };
+    } else if (this.curTokenIs(TokenType.DROP) ||
+      (this._isKeywordAsIdent() && this.curToken.value.toUpperCase() === 'DROP')) {
+      action = 'DROP';
+      this.nextToken();
+      // Optional COLUMN keyword
+      if (this.curToken.type === TokenType.IDENTIFIER && this.curToken.value.toUpperCase() === 'COLUMN') {
+        this.nextToken();
+      }
+      const colName = this.expectIdentifier('column name');
+      return { type: 'ALTER_TABLE', name: tableName, action, column: { name: colName, type: 'string' } };
+    } else {
+      throw this.error('Expected ADD or DROP in ALTER TABLE');
+    }
+  }
+
+  // ===================================================================
+  //  TRUNCATE TABLE
+  // ===================================================================
+
+  private parseTruncateTable(): TruncateTableStatement {
+    this.expect(TokenType.TRUNCATE);
+    this.expect(TokenType.TABLE);
+    const tableName = this.expectIdentifier('table name');
+    return { type: 'TRUNCATE_TABLE', name: tableName };
+  }
+
   // ===================================================================
   //  DROP TABLE
   // ===================================================================